1. Field of the Invention
Methods and apparatuses consistent with the present invention relate to analyzing audio and video signals and interdependently enhancing each audio and video signal with regard to a multimedia input sequence including audio and video signal components, and more particularly, to analyzing characteristics of a component of an audio signal, controlling a video signal based on the analyzed characteristics of the audio signal, analyzing characteristics of a component of the video signal, and controlling the audio signal based on the analyzed characteristics of the video signal, thereby enhancing quality of an output sequence that can be eventually experienced by a person.
2. Description of the Related Art
Related art methods of enhancing audio and video quality process audio and video signals in their respective domains and control each output audio and video signal.
For example, related art methods of processing audio and video signal are shown in FIGS. 1 and 2.
FIG. 1 is a block diagram of a related art apparatus of reinforcing low and intermediate frequency components of an audio signal.
A small-sized speaker mounted in a portable device such as a notebook personal computer (PC) or an MP3 player does not fully reproduce the low frequency component of the audio signal due to the physical limitation of its small size, which causes distortion in sound quality. An audio signal processing apparatus below has addressed this side effect and reinforces the low and intermediate frequency components of the audio signal without causing variation in sound quality.
Referring to FIG. 1, the apparatus of reinforcing low and intermediate frequency components of the audio signal comprises a filter unit 110 including a first band pass filter 111 and a second band pass filter 112, a harmonics signal generator 120, a harmonics signal controller 130, and a signal combiner 140.
The first band pass filter 111 separates a signal having a low frequency band (between 20 Hz and 200 Hz) from the audio signal. It is unnecessary to process an audio signal included in a band that is not reproduced according to the characteristics of an audio signal reproducing apparatus. To this end, the band pass filter, rather than a low pass filter, is needed.
The second band pass filter 112 separates a signal having an intermediate frequency band (between 200 Hz and 2 KHz) from the audio signal.
The harmonics signal generator 120 generates a plurality of harmonics signals using the band pass filtered audio signals. The harmonics signals can be generated through single side band modulation. The single side band modulation uses one of upper side band and lower side band signals that are generated through amplitude modulation (AM), which reduces by half an occupied frequency bandwidth and transmission power consumption.
The harmonics signal controller 130 controls the energy volume of the harmonics signals generated by the harmonics signal generator 120.
The signal combiner 140 combines the harmonics signals controlled by the harmonics signal controller 130 and the audio signal, reinforces the low and intermediate frequency components of the combined signal, and outputs an audio signal having the reinforced low and intermediate frequency components.
FIG. 2 is a block diagram of a related art apparatus for enhancing a video signal of an image processing system. In particular, the apparatus enhances an image based on a color gamut and skin tone.
Referring to FIG. 2, the video image enhancing apparatus comprises an image enhancement unit 210, a color gamut range detection unit 220, a luminance adaptation processing unit 230, a saturation adaptation processing unit 240, and a hue adaptation processing unit 250.
The image enhancement unit 210 enhances an image of a luminance signal that is input using general image enhancement algorithm and outputs the image enhanced luminance signal Yenh.
The color gamut range detection unit 220 detects a maximum value Ymax and a minimum value Ymin of luminance expressed by a given pixel and a maximum value Cmax and a minimum value Cmin of a chrominance signal using input saturation signal C and hue signal H.
The luminance adaptation processing unit 230 outputs an image enhanced luminance signal YYA based on mapping of the color gamut. In more detail, the luminance adaptation processing unit 230 adaptively determines the luminance signal YYA based on the relationship between a luminance Y value of the given pixel and the maximum value Ymax of the luminance signal within the scope of the color gamut detected by the color gamut range detection unit 220, or the relationship between the luminance signal YYA based on the relationship between the luminance value Y of the given pixel and the minimum value Ymin of the luminance signal within the scope of the color gamut detected by the color gamut range detection unit 220. Yenh denotes the image enhanced luminance signal provided by the image enhancement unit 210. Ymax denotes a maximum value of luminance expressed by the given pixel.
The saturation adaptation processing unit 240 outputs an image enhanced saturation signal CCA based on the mapping of the color gamut using the relationship between a value of the saturation signal C of the given pixel and the maximum value Cmax or the relationship between the value of the saturation signal C and the minimum value Cmin within the scope of the color gamut provided by the color gamut range detection unit 220. C denotes is the saturation signal of an input pixel. Cmax denotes a maximum value of saturation expressed by the given pixel. CCA denotes the adaptively image enhanced saturation signal based on the mapping of the color gamut. H denotes the hue signal.
The hue adaptation processing unit 250 outputs image enhanced luminance YHA and saturation CHA based on a skin ton region using the luminance Y of the given pixel, the image enhanced luminance Yenh, and the adaptively image enhanced luminance YYA provided by the luminance adaptation processing unit 230, and the saturation C of the given pixel, the hue H, and the adaptively image enhanced saturation CCA provided by the saturation adaptation processing unit 240. Y denotes the luminance of the input pixel. Yenh denotes the image enhanced luminance provided by the image enhancement unit 210.
As described above, the audio signal or the video signal is processed in each domain using a variety of methods so that a signal having a specific enhanced component can be output.
However, quality of an output sequence that can be experienced by a person who is an end user is not experienced interdependently from visual and auditory sense but is determined by simultaneous stimuli via interaction.
Therefore, a method of adaptively controlling a video signal based on the characteristics of an input audio signal or adaptively controlling the audio signal based on the characteristics of the video signal and interdependently enhancing output sound and image is needed.